Abstract

Purpose

The relation between driving pressure (plateau pressure-positive end-expiratory pressure) and mortality has never been studied in obese ARDS patients. The main objective of this study was to evaluate the relationship between 90-day mortality and driving pressure in an ARDS population ventilated in the intensive care unit (ICU) according to obesity status.

Methods

We conducted a retrospective single-center study of prospectively collected data of all ARDS patients admitted consecutively to a mixed medical-surgical adult ICU from January 2009 to May 2017. Plateau pressure, compliance of the respiratory system (Crs) and driving pressure of the respiratory system within 24 h of ARDS diagnosis were compared between survivors and non-survivors at day 90 and between obese (body mass index ≥ 30 kg/m2) and non-obese patients. Cox proportional hazard modeling was used for mortality at day 90.

Results

Three hundred sixty-two ARDS patients were included, 262 (72%) non-obese and 100 (28%) obese patients. Mortality rate at day 90 was respectively 47% (95% CI, 40–53) in the non-obese and 46% (95% CI, 36–56) in the obese patients. Driving pressure at day 1 in the non-obese patients was significantly lower in survivors at day 90 (11.9 ± 4.2 cmH2O) than in non-survivors (15.2 ± 5.2 cmH2O, p < 0.001). Contrarily, in obese patients, driving pressure at day 1 was not significantly different between survivors (13.7 ± 4.5 cmH2O) and non-survivors (13.2 ± 5.1 cmH2O, p = 0.41) at day 90. After three multivariate Cox analyses, plateau pressure [HR = 1.04 (95% CI 1.01–1.07) for each point of increase], Crs [HR = 0.97 (95% CI 0.96–0.99) for each point of increase] and driving pressure [HR = 1.07 (95% CI 1.04–1.10) for each point of increase], respectively, were independently associated with 90-day mortality in non-obese patients, but not in obese patients.

Conclusions

Contrary to non-obese ARDS patients, driving pressure was not associated with mortality in obese ARDS patients.

Notes

Author contributions

AJ contributed to the conception and design of the study, analysis and interpretation of data, drafting the submitted article and providing the final approval of the version to be published. JC contributed to acquisition of the data, analysis of the data, drafting the submitted article and providing final approval of the version to be published. DV contributed to the acquisition of the data and providing the final approval of the version to be published. CM contributed to the acquisition of the data and to providing final approval of the version to be published. JC contributed to the acquisition of data and drafting the submitted article. MC contributed to the acquisition of the data and providing final approval of the version to be published. MC contributed to the acquisition of the data and providing final approval of the version to be published. FB contributed to the acquisition of the data and providing final approval of the version to be published. NM contributed to the acquisition of the data and providing final approval of the version to be published. GC contributed to the analysis and interpretation of the data and to providing final approval of the version to be published. SJ contributed to the conception and design of the study, analysis and interpretation of data, drafting the submitted article and providing final approval of the version to be published.

Funding

Support was provided solely from institutional and/or departmental sources.

Compliance with ethical standards

Conflicts of interest

Dr. Jaber reports receiving consulting fees from Drager, Hamilton, Maquet and Fisher & Paykel. No potential conflict of interest relevant to this article was reported for other authors.

Ethical approval

Approval from the local scientific and ethics committee of the “Comité d’Organisation et de Gestion de l’Anesthésie Réanimation” (COGAR) of the Montpellier University Hospital was obtained; they stated that no informed consent of the patient or next of kin was required because there was no change in care practices.